f(x)=(sinx-cosx)sin2x/sinx.==2cosx(sinx-cosx)=sin2x-2cos²x=sin2x-(1+cos2x)=sin2x-cos2x-1=√2(√2/2sin2x -√2/2cos2x)-1=√2sin(2x-π/4)-1最小正周期T=2π/2=π由-π/2+2kπ≤2x-π/4≤π/2+2kπ-π/8+k...